ABB ACS880-x04, Firmware Manual

Page: 54 / 604

54 Program features
• ( 90.62 Gear denominator = 1)
(These parameters need not be changed as position estimate is not being used
for feedback.)
•
90.63 Feed constant numerator = 7
• 90.64 Feed constant denominator = 10
The load moves 70 centimeters, ie. 7/10 of a meter, per one revolution of the
cable drum.
The load height in meters can be read from 90.07 Load position scaled int , while
90.03 Load speed displays the rotational speed of the cable drum.
Example 2: Using two encoders
One encoder (encoder 1) is used for motor feedback. The encoder is connected to
the motor shaft through a gear. Another encoder (encoder 2) measures the line
speed elsewhere in the machine. Each encoder is configured as shown in
Configuration of HTL encoder motor feedback above. In addition, the following
settings are made:
• ( 90.41 Motor feedback selection = Encoder 1 )
• ( 90.43 Motor gear numerator = 1)
• 90.44 Motor gear denominator = 3
The encoder turns three revolutions per one revolution of the motor shaft.
•
90.51 Load feedback selection = Encoder 2
The line speed measured by encoder 2 can be read from 90.03 Load speed . This
value is given in rpm which can be converted into another unit by using 90.53 Load
gear numerator and 90.54 Load gear denominator . Note that the feed constant gear
cannot be used in this conversion because it does not affect 90.03 Load speed .
Example 3: ACS 600 / ACS800 compatibility
With ACS 600 and ACS800 drives, both the rising and falling edges from encoder
channels A and B are typically counted to achieve best possible accuracy. Thus the
received pulse number per revolution equals four times the nominal pulse number of
the encoder.
In this example, an HTL-type 2048-pulse encoder is fitted directly on the motor shaft.
The desired initial position to correspond the proximity switch is 66770.